206 BOTANICAL GAZETTE [SEPTEMBER 
play an important réle in determining the difference in behavior 
of these two organisms. 
TABLE X 
DRY WEIGHT (IN MILLIGRAMS) FORMED BY shred oxysporum AND 
F. trichothecioides IN 6 
| 
es 
2 
Discussion.—The versatility of these organisms in using various 
carbon sources in their metabolism is of great interest. This almost 
omnivorous ability to use carbon compounds, including the simplest 
fatty acid, the highly oxidized fatty acids, the long carbon chain 
acids, the alcohols, mono- and poly-hybic, glycerin and fats, the 
mono-, di-, and poly-saccharides, including the dextrines, starches, 
hemicelluloses, and true celluloses, assigns to them an important 
rdle in the carbon cycle, and at the same time must help render 
them the formidable and destructive enemies of the root crops that 
they are. 
The methods suggested by Appet (2), namely, rigid inspection 
of potato fields, immediate destruction of all plants that show the 
slightest symptoms, quarantining of non-certified seed stock, alone 
give promise of keeping these troubles in check. Disinfection of 
storage cellars and of potatoes when put into storage, together with 
storage at proper temperature, will help combat these diseases, 
especially the dry rot induced by F. trichothecioides. 
Percentage solanin 
Fusarium oxysporum.... 
Fusarium trichothecioides 
Conclusions 
1. Fusarium tuberivorum Wilcox and Link is the same as Fusa- 
rium trichothecioides Woll. 
2. Both Fusarium oxysporum and F. trichothecioides can produce 
both tuber rot and wilt of the potato plant. 
3. The wilt is induced by destruction of the root system and 
by clogging of the xylem elements in the stem, and is, in mild 
cases, marked by such symptoms as discoloration of leaves, curling 
and rolling of leaves, and production of aerial tubers. 
